Toxoplasmosis is caused by parasite Toxoplasma gondii, which is transmitted through meat containing T. gondii cysts or water containing oocyst from feline feces. T. gondii infection in human can make eye and brain injuries, systemic illness and even death. Toxoplasma gondii can exist in two cellular stages: a rapidly proliferating tachyzoïte form, and a latent encysted bradyzoite form, which remains in the body for the duration of the lifetime of the host, maintaining the risk of recurrence. There are currently no effective treatments against the bradyzoïte form. Available medicaments which target the tachyzoïte form, such as pyrimethamine and sulfadiazine, present also high toxicity and hypersensitivity.
An international application PCT/EP2011/004055 discloses that hydroxybenzamide has a good antiparasitic activity, but it presents only a moderate activity against intracellular form of Leishmania. 
Document US2003/013757 A1 discloses aromatic dicarboxylic acid derivatives,
including a compound of formula:
with anti-tumor cell-proliferation activity.
Recently, several Histone deacetylases (HDAC) inhibitors with anti T. gondii potential were characterized (Strobl et al., J Parasitol. 2007; 93(3):694-700; Bougdour et al., Exp Med. 2009, 206(4):953-66; Maubon et al., Antimicrob Agents Chemother. 2010, 54(11):4843-50). Histone deacetylases play key roles in epigenetic regulation and in various intracellular processes (Tang et al., Clin Sci (Lond). 2013. 124 (11): 651-662. They act through the modification of histone and non-histone proteins leading to transcription repression. Increasing amounts of evidences indicate that histone deacetylase are promising drug target in various parasitic born diseases (Andrews et al., Immunol Cell Biol. 2012, 90(1):66-77). It was observed that apicidin, a fungal metabolite with nanomolar HDAC inhibitory activity, express a strong antiparasitic activity against Plasmodium falciparum (Darkin-Rattray et al., Proc Natl Acad Sci USA. 1996, 93(23):13143-7). Additionally, some classes of HDAC inhibitor express a broader spectrum of antiparasitic activity acting on Plasmodium falciparum and Leishmania (Mai et al., Antimicrob. Agents Chemother. 2004, 48:1435-1436). The Toxoplasma gondii genome contains five putative class-I/II HDAC homologues (Toxobd.org). Among them, TgHDAC3 is a part of a large multi-protein complex termed the T. gondii co-repressor complex, whose deacetylase activity is sensitive to HDAC inhibitors. T. gondii HDACs have also been shown to function in stage-specific gene regulation during the differentiation from tachyzoites to bradyzoites (Saksouk et al., Mol Cell Biol 2005, 25: 10301-10314). Recently, novel derivatives of the tetrapeptide FR235222 with inhibitory T. gondii activity have been synthesized (Maubon et al., 2010).
However unfortunately, HDAC inhibitors known in prior art need to be used in high concentration to inhibit parasite growth and additionally most of HDAC inhibitors show little selectivity for the intracellular stage of parasites compared with their selectivity for human cells or for specific HDAC. This low specificity, lack of selectivity and/or in vivo activity of HDAC inhibitors have therefore greatly hampered the development of an HDAC inhibitor based T. gondii therapy.
Therefore, the development of new medicaments with a high selectivity index against T. gondii remains challenging and is urgently required.